A propeller is a device to convert torque into thrust, thereby converting rotational motion into linear motion by accelerating fluid axially. For a propeller to generate the maximum amount of thrust with the least amount of shaft power input, a combination of high blade pitch and low rotational speed is of advantage.
The maximum pitch that can be applied to the propeller is in practice limited by the velocity of the fluid it is operated in. If the incoming fluid velocity is low or zero, the propeller blade will experience stall at too high pitch angles and will not move any fluid at all. A fan or static thruster which operates in zero velocity conditions is therefore limited in how efficient it can operate due to pitch angle constrains.
The object of this invention is to provide a propeller that can be operated at high blade pitch angles at zero fluid velocity inflow conditions without stalling, delivering equivalent thrust at significantly reduced power input levels when compared to conventional type propellers, or at least provides the public with a useful alternative to conventional propellers.